There is a growing interest in the addition of specific ingredients or additives to food, feed, detergents, cosmetics, chemicals etc. The form wherein these ingredients or additives are added will depend on the physical and chemical characteristics. Some components are so active that they have to be added in diluted forms, others are prone to oxidation or are very hygroscopic so that they have to be packaged in one form or another.
One way of packaging the ingredients or additives is by enclosing them in capsules other possibilities include the enclosure or entrapment in a gel or gellifying agent or the binding to a carrier.
Different types of carrier materials are known, depending on the specific component and on the desired application a carrier is chosen. For some applications or components there are still no suitable carriers available. Starch-based carriers have been investigated for some time. In general when starch is used as a carrier the final, loaded particles are not strong or hard enough. Alternatively they do not degrade fast enough.
British Patent Application GB 2,311,534 A discloses starch particles comprising 30-95% starch and/or low-protein flour; 0.1-50% silicon dioxide; and 5-15% water. As indicated in the summary of the invention, bridging pages 1 and 2 the silicon dioxide is added to improve the flowability of starch granules.
European Patent Application EP 402 186 A discloses a process for preparing directly compressible starch. In this process a part of the starch is heated for some time to around 80.degree. C. This temperature is however not enough to fully pregelatinise the starch.
Japanese patent application JP 56028606 relates to the preparation of granular potato starch. It discloses a process wherein potato starch is charged in a fluidising granulator and a solution of gelatinised potato starch is sprayed as a binder. The fluidised potato starch agglomerates and grows surrounding the binder nucleus to obtain fine granular potato starch.
PCT application WO 95/19376 relates to a porous particle aggregate and methods for the preparation thereof. It relates to substantially spherical porous aggregates of starch granules bound together with a binder at least at their points of contact and said starch granule aggregates having an average diameter of about 5 to about 250 microns. The porous particle aggregate is prepared by spray-drying.
There is a need for a carrier material consisting of substantially spherical particles with an improved hardness and composed of starch exclusively. Such a product can therefore easily be applied in food, feed and pharmaceutical applications.